Architecture Overview
This library provides a robust plugin system for enhancing PixiJS with deferred lighting capabilities, enabling dynamic and complex lighting effects for 2D graphics. Developers interact with the @pixi/lights package, which serves as the central hub for integrating deferred lighting. Through this package, users can access various light types, such as AmbientLight and PointLight, and manage the lighting system's integration with their PixiJS renderer and stage.
Under the hood, the PixiJS Lights plugin employs a deferred rendering pipeline, leveraging PixiJS's @pixi/layers extension. This architecture separates geometry and lighting passes to optimize performance and achieve richer visual atmospheres. The LightRenderer orchestrates this multi-pass drawing process. It collects active light sources and binds necessary textures, such as diffuse and normal maps, often identified via a LayerFinder. Each light is then rendered using its associated LightShader, a crucial module responsible for the complex per-pixel lighting calculations performed on the GPU.
The LightShader is the engine for performing sophisticated graphical computations required for realistic lighting. It manages the compilation and usage of GLSL shaders, acting as the bridge between JavaScript logic and the GPU's rendering capabilities for lighting effects. This modular design, relying on shader utilities, allows for easier updates and extensions of lighting algorithms. The LightRenderer then binds these shaders and textures to execute the lighting pass, ensuring combined lighting effects are correctly applied to the final output.
The AmbientLight provides a foundational lighting component, simulating indirect illumination by offering a constant, scene-wide brightness. This ensures no part of the scene is completely devoid of light, contributing to a more realistic visual result. Complementing this, the PointLight models common real-world illumination, emitting light from a specific location with a decaying intensity. This allows for the creation of localized highlights and atmospheric effects, enabling developers to sculpt scenes with more depth and realism.
This architectural approach is designed for extensibility and maintainability. By separating concerns between light types, shader management, and the rendering orchestration, the plugin allows developers to easily adopt advanced lighting features without deep dives into the core PixiJS renderer.
For contributors, understanding the interplay between LightRenderer, LightShader, and the individual light types is key. Starting with the @pixi/lights package reveals how these components are exposed and managed. Examining LightRenderer.ts provides insight into the pipeline orchestration, while LightShader.ts is essential for understanding the GPU computations. Familiarity with PixiJS's rendering pipeline and GLSL shaders will be beneficial for contributing to the core lighting logic.